Hi. I Was Given A Ultrasound On My Pelvis And

Hi. I was given a ultrasound on my pelvis and abdomen because I am having severe stomach pains and having to go the toilet for a poo a lot... like 6-7 times a day. I had an ultrasound and the nurse doing the ultrasound said that there us a shadow in my abdomen area and to make an emergency appointment with my Dr to discuss the results of the ultrasound. My appointment is tomorrow afternoon & I'm worried. What would you say it could be?